A Thin Film Transistor Liquid Crystal Display (TFT-LCD) has the advantages of small volume, low power consumption, no radiation et al., and occupies the dominant position in the current market of the flat panel display.
TFT-LCD has obtained the rapid development for the last few years, especially the liquid crystal television, and its size and resolution are improved continually. The liquid crystal television with large size and high resolution has become a mainstream for the development of the TFT-LCD. At present, the world's largest liquid crystal television has the size larger than 100 inches. As the continual increase of the TFT-LCD size and the improvement of the resolution, the driving circuit with higher frequency is usually adopted in order to improve the display quality.
However, the carrier mobility of the current amorphous silicon (a-Si) thin film transistors can not meat the demand due to the continual increase of the TFT-LCD size and the frequency of the driving circuit. The carrier mobility of the a-Si thin film transistors is typically at about 0.5 cm2/VS. The current carrier mobility of the a-Si is obviously hard to meet the demand when the LCD size is over 80 inches and the driving frequency is 120 Hz, which needs the carrier mobility more than 1 cm2/VS. Although the poly-Si thin film transistor has high mobility, it is rarely used because of its poor uniformity and complex manufacturing process.
The metal oxide thin film transistor has attracted attentions and become a study focus of the large size, high refresh frequency LCD and organic light emitting diode (OLED) panels because of its high mobility, good uniformity and transparency, and simple manufacturing process, which can meet the requirements of the manufacturing process and the electrical properties for used in the large size LCD and active organic electroluminescence.